Dehydrating apparatus



Patented Oct. 2, 1945 vmiHimna'rnsof APPARATUS Bertram Fair Lundy, Vancouver, British Columbia. Canada Application lzlclaiins My invention relates to improvements in dehydrating apparatus and process, which are par- August 20, 1942, In Canada August Serial No. 455,540 6, 1942 (ci. sia-23s) ticularly adapted for use in dehydrating fibrous Y or pulpy substances such alfalfa hay. and fruit.

The objects of the invention are toprovide means for progressively applyingpressure tothe product to be treated to extract the bulk of its as peat. vegetables.

moisture; to dehydrate `the partially dried product by passing same at sub-'atmospheric pressure.

the body 2 and the liner 26. The liner 26 is tapered to conform to the taper-of the feed screw and is provided intermediate its length with seepage orifices 21 which are preferably formed as detents pressed out of the wall of the liner at such f an angle that moisture flowing therethrough will through one or more heated zones and restoring to said product any vitamin containing com-f ponent which was extracted with the moisture l content which was driven oil in-the' primary compressive step of the process. A further object of the invention is to provide means whereby a i greater amount of the water content" of the procluct is removed in the ilrst compressive step than is usually obtained. In describing the invention reference willhe made to the attachedl drawing in which:

Fig. 1 is a diagrammatic sectional view of the invention.

Fig. 2 is a sectional view of the feed screw and liner of the screw press.

pass in a direction counter to the flow of material through the liner, thus preventing said ori-- ces from clogging.

The discharge cone l isprovided with a flange 28 which seals the outer end of the body 2 and the length and taper of the cone is such that the material -thrust therethrough by the rotation of the feed screw will form an effective lock against the ow ofair through the mass.

'Ihe discharge end of the screw press i is connected by an air tight chute 32 to one or more I dehydrating chambers to vbe hereinafter de? Inthc drawing like charactersl of reference indicate corresponding parts in each figure.

The numeral i indicates generally a screw` press having a tapered body 2, a head 3, a hopper t and a discharge cone 5. The head 3 is a boxiike structure having bearings 6 and I in which are iournalled afscrew assembly 3 `whichis shownv more particularly in Figure 2. The screw assembly consists of a short shaft!) rotatable in the bearing l, whichshaft is recessed as at III and provided with a plurality of peripheral openings li and a flange i2. Fitted to the flange is a gear id having a concentric yond the face of the gear and beyond the openings il f the shaft 9 and tted to the gear and the flange I2 is a feed screw I'I.

The feed screw il consists of a hollow stem I8 having a tapered core I9 and is provided with a helical flight 2D which decreases progressively to ward its free end and is internally grooved as-at 2i. The stem I8 is perforated as at 22 throughout its length between the convolutions of the night so as to permit the outflow of Juices from the product through the core I3 and the openings II of thev short shaft 9 into the head 3, and the ight is provided with serve the same purpose.

The head 3 is separated 'from the tapered body' by a wall 24 which is provided with an opening 25 communicating with the interspace between bell I5 which projects be-y scribed. Within the chute 32 is a rotary hammer mill 33'which is driven by any suitable means. v The mill is provided with floating hammers 34 which comminute the material extruded from the discharge cone 5 to a state of appropriate flneness. The chute 32 communicates with a hermetically sealed dehydrating'chamber 36 in which is provided an endless belt 3l suitably driven. which carries the ground material to the opposite end of the chamber and allows it to iall into a chute 38 and from thencel into another dehydrating chamber indicated by the numeral 39. Y

The chambers 36 and 39 are of similar construction and varelprovided with similar parts, all of which are indicated by similar numerals. Steam pipes 42 are arranged horizontally below the belt 31 to provide heat for dehydrating purposes and suction pipes 43 are fitted to each chamber which e connect with'a suitable vacuum pump, not shown,

to Withdraw the vapours from the chambers and maintain the interior of said chambers at a suitable sub-atlnospheric pressure.

-While 'two dehydrating chambers only are l shown, it will be understood that a greater numv l ber may be used, according to the nature of the passages 23 which material kto be processed.

The 'dehydrating chambers maybe rectangular or cylindrical and may be equipped with any desired type of conveyor system without departing from the spirit of the invention.

The chamber 39 is provided with a discharge chute Il which leads to a baling press 45 or other suitable device. The chutes 32, 38 and .Il are each provided with a pivotally mounted flap 4B which is capable of movement to `restrict or otherwise control, the flow of materialiat various points from the screw press to the baling 2 l l l 2,886,052

press 45. These flaps are also designed to substantially close off the air flow in the system, so that if it is desired to maintain a higher Vacuum temporarily or an increase in temperature in the dehydrating chamber 36 than in the chamber 39 the ap in chute 38 may be closed.

The numeral 50 indicates a steam heated evaporator of any desired type, Vwhich is supplied with high vpressiire'"steam'through pifp h d 52. The feva'poratorcs `provided withi'an 1 e 53 connecting with a pipe 54 from the boxlike head,4 3, a vapour discharge outlet 55 and a liquid ex` tract outlet 56. The outlet 56 communicates through a pipe 51 with a pump 58=Which charges through a riser 59 and aspra'yp'ipe tending transversely above the belt 31 'of he dehydrating chamber 39.

The operation of the sys alfalfa hay would be as follows: i

The hay would be fed into the hopper' sreaidezsrofzsthe hammer mil1,so :thatQitf-zmay v,fall inezasubstanY-fi lmeans for conveying?- tiallyxeveu. layer-,tombe vconveyor ,beit-:-sismiche; dehydrating chamber zsf'by ywhich itffimcarriedii andheated vto moistureevaporating temperaturen S0 :that the `.Water Vcontent may, .be drawnroff asx it'evaporates'. ,'-The mass; having hadit'srin' sturefo wie. A as ya vehicle `duringfthe,sprayingfpracess is eva Dol'tedgQlltifrOm the 'materialisprayed::therwi during `itstravel through the dehydratingfcham ber 39, so that the nal product is commercially dry as it is delivered to the baler 65.

Since the only entrance into the air tight chute 32 is through the discharge cone 5, and since,

5 as previously pointed out, the thrust of the compacted material through this long cone eiectively prevents they free passage of air into the @713:2 andlldghydratinggchamber 36, while the ocksrthejfree passage of air up nd chamber 39, it is possible to maintain a partial vacuum in the dehydrating chambers, and this may be further controlled by theflapsillllifi 'Ihe maintenance of partial vacuum or reduced air pressure in the dehydrating chaman important feature in my invention 'since it reduces the amount of heat required for afdehyl-ratiofiand enables the desired dehyation to take place in a shorter period of time. Th results in less possibility of vitamin loss dur- 20 ing the'dehydratlon of the comminuted material. v- Whatl I claim 'as' -m'y 4invention is:

f 1*.A dehydrating apparatus comprising a screw pressvhaving a feedl hopper andl a discharge cone,

25 a dehydrating chamber, a chute `extending betweenuthe? discharg'cone andthe dehydrating chamberysaiddehydrating chamber -having an thexchut fo comminutingi'thematerial Apassing f 'sffor" conveying the com- 'd dieting chamde :,'wale'pemg vided, 111th' 1 sie., Y l andE ari outlet; lirnpa'ctirieans' 'Within 4the chute f or comminuting the, material passing through/'the progess'ively'through he separatefz'ones 'ofV the dehydratingchamber an means for separately sealing each-z y h yv'dierent pressures or ntemperature` 'rn' be Yelec ively ,m' ntain'ed in saidffz'on'esf1 f e anda-discharga a drivin.` Sear..-f0r head, ffsaid feedl screw erfora'tions ,com-

gear,

asl tlfextrudes lfrom the dis-.

eclonuninnted" x'naterial Vbxiiiie head ody; a feed screw.

andvjthejnerysaid,

andfmeans the maar@ 1 e hopper an a discharge, a

perforated liner within the body, a feed screw within the liner, a shaft and driving gear for the feed screw within the head, said feed screw having a hollow core and peripheral outlet orifices communicating between the core and the liner, said core being extended through 'the gear and means for discharging liquid entering the core into the boxlike head and an annular bell concentric with the gear and extending beyond the peripheral outlet orifices.

6.l Dehydrating apparatus comprising a continuous feed press having a discharge opening adapted to express material acted upon in asubstantially solid cylindrical air tight mass, a dehydrating chamber having an inlet and an outlet, said inlet being directly connected With the discharge'opening, means for disintegrating the mass as it extrudes through said discharge opening,`and means connected with the dehydrating chamber outlet for utilizing the material dehydrated to seal said outlet, and thereby enable lower air pressure to be maintained in said chamber.

7. Dehydrating apparatus comprising a feed press and a dehydrating chamber having an inlet and an outlet, said inlet connected with said feed press, means for maintaining a seal at the inlet and the outlet of. the dehydrating chamber, whereby to enable a partial vacuum to be maintained in said chamber, means for reducing the air pressure in said chamber, a conveyor extending through the dehydrating chamber, means for `tracted liquid, and means for mixing ,the remainder with the material in one of the zones. Y 10. Adehydrating apparatus comprising a continuous feed press having' a discharge opening, a dehydrating chamber having an inlet and an outlet, means for maintaining a partial vacuum in said chamber, said discharge opening constituting the only entrance to the inlet of the dehydrating chamber, said press being adapted to urge material in solid cylindrical form through the discharge opening in such manner as to form a constant seal between the press and the dehydrating chamber and thereby aid in maintaining the partial vacuum in'said chamber, means for comminuting the solid material in the inlet, a

` conveyor for the material in said chamber, means for compressing material passing through the outlet so as to effect a continuous air seal at the outletend of said cllamber, heating media within the dehydrating chamber, whereby continuous passage of material through said chamber and dehydration of said material under favorable `conditions of heat and reduced air pressure can take place.

1-1. A dehydrating apparatus comprising a y continuous feed press having a dischargeopenl ing, a dehydrating chamber having an inlet and extracting liquid from the material fed into the V' press, means for evaporating some of the extracted liquid, and means for delivering the residue onto the material in the dehydrating chamber.

8. Dehydratlng apparatus comprising a feed press adapted to Vprovide a continuous feed andv a dehydrating chamber having an inlet and an outlet, said inlet connected with said feed press, means for maintaining a seal at the inlet and the outlet of the dehydrating chamber, whereby to enable a partial vacuum to be maintained in said chamber, a conveyor extending through the dehydrating chamber, a heating media within the chamber, means for reducing the pressure Within said chamber below atmospheric pressure, means for extracting liquid from the material fed into the press, means for evaporating some of the extracted liquid and means for delivering the residue onto the material in the dehydrating chamber.

9. Dehydrating apparatus Vcomprising a feed press and a dehydrating chamber having an inlet and an outlet, means for maintaining a seal at the inlet andthe outlet of the dehydrating chamber, whereby to enable reduced air pressure to be maintained in said chamber, a conveyor extendingfthrough the dehydrating chamber, said de hydrating chamber being divided into connected zones, heating media in some of the zones, means for reducing the pressure within some of the zones belowatmospheric pressure, means for extracting liquid from' the material fed into the press, means for. evaporating` some of the exan outlet, means for maintaining a partial vac-l uum in said chamber, said discharge opening constituting the only entrance to the inlet of the dehydrating char ber, 'said press being` adapted to urge material in solid cylindrical form through the discharge opening in such manner as toform a constant seal between the press and the dehydrating chamber and 4thereby aicl in maintaining the partial vacuum in said chamber, a conveyor for the material in said chamber, means for compressing material passing through the outlet so as to effect a continuous air seal at the outlet end of said chamber, heat- 'ing media within the dehydrating chamber. whereby continuous passage of material through said chamberand dehydration of said material under favourable conditions of heat and reduced air pressure can take place.

12. A dehydrating apparatus including a feed press, a dehydratingchamber having an. inlet and an outlet, means, for maintaining a partial vacuum in said chamber, said feed press dis charging into 'said inlet, the only entrance into 'said inlet beingby way of said feed press. whereby the operation of said press upon material therein will aid in maintaining the partial vacuum in said chamber, a conveyor for material in said chamber, means for compressing mate` 

